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[Andyn]

As many of you know, I don't do electric boats, or in fact anything that doesn't make an awful lot of noise...


So then, to start my engines I've always used the typical model starters, which have always been nothing but a pain in the rear. The buttons are always in the worst places and are either too sensitive or rubbish, plus they weigh a ton. My current starter is a 4:1 geared type, run off a 14.8 Li-Po. It's mostly good enough for the 45 motors, my 12's like it, but a CMB 90 full of fuel will barely turn over.


What I aim to do is make myself a new starter, using a brushless motor at around 36mm diameter that runs off the 14.8 Li-Po, I'll make up a handle etc for it, that's all fine.


The issue I have is that with a brushed motor you press a button and off it goes, obviously I will need to be able to do the same with this. Suggestions?

[malcolmfrary]

A brushless motor will need an ESC of the right voltage (for the battery)and current rating (depends on what the motor will want at the load it is going to handle) to do the job that brushes do.  The ESC will need a signal source to tell it what to do.  This could be a spare channel on the radio, or, for a stand-alone, a servo tester.

[Andyn]

Perhaps I should further clarify - I need a device that will provide an ESC with a signal which is either full off or full on, at the push of a button.

[malcolmfrary]

Simplest, down and dirty way is two servo testers, one set to your chosen "on" value, the other to "off" and a switch to select between one and the other.  ESC testers, the last time I looked, were about £2 each, delivered, from various ebay sellers.

[tsenecal]

why do you feel a brushless motor is necessary for this device?

[Andyn]

Simplest, down and dirty way is two servo testers, one set to your chosen "on" value, the other to "off" and a switch to select between one and the other.  ESC testers, the last time I looked, were about £2 each, delivered, from various ebay sellers.

That may well work, not sure how much the ESC would like the loss in signal between the two though. For the sake of 4 quid, it's worth a try

why do you feel a brushless motor is necessary for this device?

See original post.

[tsenecal]

first post does not indicate a need for a brushless motor.  first post indicates a need for more torque.

[chas]

I was also wondering why a brushless motor, especially as more torque is needed. It's not my area, but I was wondering about motor bike starter motors. They are designed for just this job.
Chas

[malcolmfrary]

That may well work, not sure how much the ESC would like the loss in signal between the two though. For the sake of 4 quid, it's worth a try



See original post.

A single tester with a modified control knob might be an answer.  The more gentle transition from "stop" to "full go" and back might be a good answer.  Combined with a hefty power switch to arm/isolate the thing - you don't want the electronics slowly draining the starter battery.
At the price, and for the usefulness offered, every home should have a servo tester.

[JimG]

I am rather surprised that a geared starter on a 4s pack is unable to start a 90 glow. These are commonly used for aircraft engines on 12V to start up to 50cc petrol engines. A 90 is only 15cc. I start a 91 glow using an ungeared starter on a 3s pack with ease. Perhaps the problem is the description of trying to start it full of fuel, if you are flooding the engine then a more powerful starter will  damage the engine with a hydraulic lock.
Jim

[Tombsy]

I’m using a direct drive Sullivan Hi-Tork on a 4s lipo and it will start my boats fairly easily, a flooded .90 you still might have to loosen the glow plug a touch until it fires. Some of the fellows here are using ATV starter motors that have a lot of torque.